''Well, we have a drought. Some people around Yuba County have lost their water supply. But here? I've been here for how many years? I built this cabin, raised a family. It must be going on seven years. Never in all that time has the stream run dry. This is really strange. I'll have to check with my neighbor upstream.'' He rushed toward the truck.

''Why not call them?'' I had for the moment forgotten that he lived a primitive life here - no telephone or electricity. Kerosene lamps gave light. A ram pump supplied water from the stream.

''Call them? With what, a megaphone? This isn't Los Angeles, Dad. This is the High Sierra foothills. You get to visit people instead of talking to disembodied voices.'' He started the engine and yelled to Margaret, his wife, what he was up to. At that moment, Reid, my four-year-old grandson, ran out of the woods.

''Well, I'll be.... You're the first one upstream from us. You've got water. I don't.'' Barry got out of the truck, and he and Jack walked toward the stream about 100 yards away.

''The stream's got no water?'' Reid asked.

''Maybe somebody dammed up the stream for some reason,'' I said. By this time Barry had returned and heard my explanation.

''Nobody would do that, Dad. We're all friends up here and respect each other's dependence on the land. Isn't that right, Reid?'' Reid gave his father a funny look and curled up like a ball against me. I wondered about him being so quiet. He usually talked a blue streak. Barry started the truck, and we headed back.

''Well, what do we do, Dad.'' He figured since I was an engineer I knew everything.

''C'mon. Don't give me that,'' I said. ''You know as well as I do what has to be done. Even Reid does. What do we have to do, Reid?'' The boy didn't answer. He looked miserable.

''Well Reid, I'll tell you what we have to do,'' said Barry, looking at me and winking. ''We're gonna have to hike up the stream and see what the problem is.''

''You gonna go up the stream?'' asked Reid, acting very surprised.

''Tell him, Dad,'' said my son, deferring to me.

''You see, Reid, at your place the stream stopped flowing. Now at Jack's place the stream is flowing great. So there must be some sort of dam that's backing up the water between your place and Jack's. Could be beavers. They're pretty good dam builders.''

''Beavers?'' asked Reid becoming very interested in what I was saying. ''We got beavers, Dad?''

''Haven't had any beavers in a long time, ever since you were born. Maybe a baby beaver found his way back here and built himself a dam. You never know. What do you think, Reid?''

''Yeah. A baby beaver.'' His voice had returned to its normal shouting self.

When we stopped at the house, Reid shot out of the truck and made a beeline for the woods.

''He's acting real funny,'' I said. ''Where did he disappear to?''

My son smiled. He did not look worried anymore. ''Follow me and be quiet,'' he said and ran in Reid's direction.

When I caught up with him, he lifted his fingers to his lips and pressed on like a native stalking prey. Barry suddenly stopped and beckoned me closer.

There was Reid up to his knees in water, frantically removing stones and mud from an earthen dam which had backed up the stream into a small lake. Barry gestured for us to turn around and go back. On the way we laughed so hard we could hardly walk.

When we got back it was late afternoon. The sun was setting fire to the clouds and filling the unpolluted sky with magenta and lavender hues. It was a lovely sight for a resident of smoggy Los Angeles. We went inside and told Margaret all about it, then decided to sit quietly for our ''baby beaver's'' return.

The door slammed. Reid came in all smiles and covered with mud. ''The stream's back,'' he screamed.

''Well what do you know?'' said Barry as he looked out the window at the babbling brook.